Deformable ears for clamp structures, which consist of two outwardly extending leg portions interconnected by a bridging portion and which are generally known as "Oetiker" ears, have been sold worldwide in very large quantities where they have enjoyed immense commercial success. These ears are used in endless one-ear or two-ear clamps, for example, as disclosed in my prior U.S. Pat. No. 2,614,304, as also in open clamps adapted to be mechanically interconnected as disclosed, for example, in my prior U.S. Pat. Nos. 2,847,742; 3,082,498 and 3,475,793. These "Oetiker" ears not only assure good holding properties but are able to compensate for thermal expansions and pressure changes to which the clamps are subjected, owing to the inherent elasticity of the plastically deformed ears. To avoid buckling of the ear during deformation when using relatively thin band material, and to increase the holding ability in the plastically deformed condition, reinforcing grooves, as disclosed in my prior U.S. Pat. No. 3,402,436 which extend in the circumferential direction of the clamp, have been used in large quantities with "Oetiker" ears during many years. The reinforcing grooves as used heretofore in the bridging portion and as described in my U.S. Pat. No. 3,402,436 consisted of a relatively narrow groove normally in the central part of the bridging portion which extended in the circumferential direction of the clamp. These prior art reinforcing grooves were of more or less V-shaped configuration as viewed in transverse cross section through the bridging portion in a plane containing the axis of the clamp structure. As viewed from above, these reinforcing grooves were more or less in the shape of a canoe or small row boat.
With the availability of new plastic materials of ever-increasing hardness, such as, "Hytrell," ever-increasing clamping forces became necessary to assure complete tightness. The holding ability of open clamp structures utilizing an "Oetiker" ear was considerably improved by the mechanical connection as disclosed in my prior U.S. Pat. No. 4,299,012 which was again further improved by the mechanical connection as disclosed in my prior U.S. Pat. No. 4,622,720. However, to fully utilize the increased strength of the improved mechanical connections, it also became necessary to provide an ear structure capable of accommodating the higher tightening forces which the improved mechanical connection could withstand. To that end, an ear structure is disclosed in the aforementioned application Ser. No. 06/922,408, the contents of which are incorporated herein by reference in which, in lieu of a canoe-shaped narrow reinforcing groove, a depression of relatively shallow depth and of generally rectangular shape, as viewed in plan view, is provided in the bridging portion of the ear (British Patent No. 2,160,577 corresponds to this last-mentioned copending application). The reinforcing depression as disclosed in this copending application also enjoyed great commercial success.